This part is a kind of semiconductor called C3851.

Function of this product has 2SC3851.

Manufacturers : Sanken electric

Image and pinout :

Some of the text within the PDF file :

2SC3851/3851A Silicon NPN Epitaxial Planar Transistor (Complement to type 2SA1488/A) sAbsolute maximum ratings (Ta=25°C) Symbol 2SC3851 2SC3851A VCBO VCEO VEBO IC IB PC Tj Tstg 80 60 6 4 1 25(Tc=25°C) 150 –55 to +150 100 80 Unit V V V A A W °C °C IEBO V(BR)CEO hFE VCE(sat) fT COB VEB=6V IC=25mA VCE=4V, IC=1A IC=2A, IB=0.2A VCE=12V, IE=–0.2A VCB=10V, f=1MHz Application : Audio and PPC High Voltage Power Supply, and General Purpose (Ta=25°C) sElectrical Characteristics Symbol ICBO VCB= 80 100max 60min 80min 40 to320 0.5max 15typ 60typ Conditions External Dimensions FM20(TO220F) 4.0±0.2 10.1±0.2 4.2±0.2 2.8 c0.5 2SC3851 2SC3851A 100max 100 Unit µA µA V V MHz pF 2.54 2.2±0.2 16.9±0.3 V 8.4±0.2 13.0min 1.35±0.15 1.35±0.15 0.85 +0.2 -0.1 0.45 +0.2 -0.1 2.54 2.4±0.2 [ ... ]

C3851 PDF Datasheet Download